1. Field of the Invention
The present invention relates to an image recording apparatus such as a copying machine or a printer in which a photosensitive recording medium is employed, and more particularly to such an image recording apparatus that prevents unused photosensitive recording medium from deteriorating due to the influence of high temperature and high moisture in the air.
2. Discussion of the Related Art
Generally, an image recording apparatus which uses a photosensitive recording medium employs, for example, as disclosed in U.S. Pat. No. 4,903,070, the disclosure of which is herein incorporated by reference, an elongated web-like microcapsule sheet coated with a plurality of photo and pressure sensitive microcapsules, each microcapsule enveloping therein a chromogenic material and a photosensitive resin, and a developer sheet coated with developing material which produces an output image upon reaction with the chromogenic material, as is well known in the art.
The image recording apparatus comprises means for receiving the elongated web-like microcapsule sheet wound around a cartridge shaft and retained in a cartridge, an exposing unit for exposing the microcapsule sheet disposed at an exposure table to form a latent image thereon, a developer sheet feeding unit for feeding a developer sheet from a developer sheet cassette, which stores therein, for example, a stack of developer sheets, toward an exposed microcapsule sheet, a pressure developing unit for pressurizing the exposed microcapsule sheet superposed with the developer sheet to thereby form an output image on the developer sheet, a separating unit for separating the exposed microcapsule sheet from the developer sheet, a taking-up unit for taking-up the separated microcapsule sheet, and a thermal fixing unit for fixing the output image on the developer sheet.
In this type of image recording apparatus, the elongated microcapsule sheet drawn out of the cartridge passes through the exposing unit, the pressure developing unit and the separating unit, and is taken up by a taking up unit. The developer sheet and superposed elongated microcapsule sheet containing a latent image are pressurized by the pressure developing unit, and are separated from each other by the separating unit and then the developer sheet is subjected to thermal fixing in the thermal fixing unit. At this time, the copying operation is completed.
In this type of conventional image recording apparatus, if a copying operation has not been executed for a long time, the unused (unexposed) microcapsule sheet which has nonetheless been drawn out of the cartridge is exposed to air located within the frame of the recording apparatus. Thus, the unused microcapsule sheet is threatened with deterioration due to the influence of high temperature and high moisture in the air within the frame, which causes a failure to reproduce the desired image.